Use modern list[int] type hint instead of deprecated typing.List

Author: changsheng0804-blip

sorts/pancake_sort.py

@@ -8,10 +8,8 @@
 python pancake_sort.py
 """
 
-from typing import List
 
-
-def pancake_sort(arr: List[int]) -> List[int]:
+def pancake_sort(arr: list[int]) -> list[int]:
     """Sort Array with Pancake Sort.
     :param arr: Collection containing comparable items
     :return: Collection ordered in ascending order of items